Frame and Body Construction
The prior art chorded zither typically incorporates a hardwood frame or pin block of either solid hardwood or laminated-ply wood material that is permanently bonded with glue to a wood top and back panel forming a hollow sound chamber and at the same time creates a rigid box structure capable as a unit of resisting the substantial forces produced by a multiplicity of 36 or 37 tuned strings (approximately 40 pounds per string). The front and back facing panels, being firmly glued to the solid wood perimeter support frame of the instrument's body are an integral composite of the string tension-resisting support structure. With this basic structural assembly there is no interchangability potential of the basic instrument involving appearance or sound chamber variations. The limitations of this traditional configuration are in the trade-offs between strength (string support), acoustical sound (thinner facing components and minimal mass), and overall weight and size (portability). A deeper frame for example would create a stronger frame with a fuller sound but would substantially increase overall weight. Lighter framing and facing materials would improve sound and weight but would be structurally less able to resist string tension, maintain tuning stability (affected by humidity), and provide consistent chord bar contact with the string plane (caused by warping). In all configurations of the prior art there is little potential for significant tonal or aesthetic modification with the same instrument frame except for string tuning variations (diatonic vs. chromatic—see also discussion below) or chording variations (changing chord bar configurations). String quantities on instruments of the prior art are generally limited to 36 or 37 by a balancing of assets based on strength, acoustics, physical size, and overall weight.
String Configurations and Quantities
A chorded zither/autoharp musician must typically make the choice between acquiring a “diatonic” or “chromatic” style instrument. The chromatic style (historically the most common) provides strings for the full range of available notes in the chromatic scale within each of the octaves of the instrument, thus including all the “sharped” strings, i.e. C, C#, D, D#, E, F, F#, G, G#, A, A#, B, C. This is analogous to providing the white and the black keys on a piano for each octave provided. The lower or bass strings are severely limited in the interests of saving space for the mid-range and higher strings which provide the capacity for melody play. The advantage of a chromatically strung and configured autoharp is that it can play any possible chord in any possible key as long as a chord bar is available on the instrument to play said chord in said key. This provides the musician with the ability to play in a few different keys with a given chord configuration and/or to include a few specialty chords (or “color chords”) which potentially enrich a given musical composition. It also allows the musician more flexibility to potentially play with musical groups who utilize keys not typically standard with the chorded zither. The definitive term for chromatic style instruments is “flexibility”. This “flexibility” of available chords is however encumbered by the inconvenience of exchanging chord bars within the chord bar frames of instruments of the prior art (see also discussion below). The introduction of “lock bars” (see also Orthey, Jr., et al. U.S. Pat. No. 5,052,259) allows a chromatic style harp to achieve one of the significant benefits of diatonic style chorded zithers by dampening out all of the strings on the instrument that are not part of the desired playing key selected by the musician, thus allowing the availability of “open chording” (strumming or plucking the strings without pressing down a chord bar. (See also discussion below regarding diatonic style chorded zithers.)
The diatonic style chorded zither on the other hand provides strings with a limited range of available notes in the chromatic scale within each of the octaves of the instrument, thus eliminating all but the diatonic strings necessary to play in the desired key(s). I.e. for the key of C the only notes available would be C, D, E, F, G, A, and B for each octave. This is analogous to providing only the white keys on a piano for each octave provided. The advantage to a diatonically strung and configured chorded zither is that although it can play in a very limited number of keys, it produces a fuller sound for each chord by increasing the number of strings that “play” with each chord. The strings that are eliminated by reduction of possible chords are converted to extra notes (i.e. doubled strings) that play in each chord. The number of overall strings that play in each chord is inversely proportional to the number of chords on the instrument. This provides the musician with the benefit of greater sound quality and fullness. Some musicians maximize this benefit by setting each instrument up to play in only one key! These instruments with their smaller overall number of chords also typically provide the musician with a greater playing area over the strings and much less potential for having problems with harmonics (the inability to effectively dampen certain strings due to their position under the chord dampening pads). “Open chording” (the ability to strum or pluck stings without dampening out any strings on the instrument) is also enhanced with the diatonic style, although “lock bars” are still necessary for each key to provide the cleanest sound with this playing technique (none is required if only one key is available on the autoharp). While the sound quality of the diatonic style instrument is much improved over ones of the chromatic style the disadvantages are great. Among them are: the need for purchasing more instruments in order to play in more keys, the inability to include specialty “color chords” in each key, the logistical problem for performers of having to travel with multiple instruments and then contend functionally with them on stage, and the greatly reduced ability to “match-up” musically with the keys played by other musicians using other types of instruments. The definitive term for diatonic style instruments is “sound quality”.
The number of strings on chorded zithers/autoharps of the prior art is usually 36 or 37, although some variations have gone to higher numbers for greater tonal range or smaller numbers of strings to produce a lighter instrument with improved vibration transfer onto the sound board. The instruments with greater numbers of strings than 37 get larger and heavier and sound quality begins to diminish, and their portability and playability in an upright-held position is compromised. To resist the greater structural tension of the strings the wood frames must be large and heavy (see also previous patents) and the potential for string-tune and flat-chord-plane destabilization is increased. Also, the potential for splitting, joint cracking, or warping failure of the wood components is increased with the higher tensioning required onto pins in close proximity to each other. A failure of this type would typically render the instrument useless. The instruments with smaller numbers of strings, while allowing improved tonal transfer from the strings to the sound chamber via the bridge, takes away from the number of strings that can be played with a given chord as well as the overall number of chords that can be accommodated on the instrument.
Chord Bar Design and Harmonics Avoidance
Chorded zithers and/or autoharps of the prior art all contain chord bars (8) which are positioned over the strings (40) and which have pre-cut string dampening pads (44). (See FIGS. 1 and 2 for a typical example of a chord bar arrangement of the prior art.) When the chord bar is pressed firmly down on the strings below, the contact of the dampening pads on the strings keeps those strings which are not part of the desired chord from sounding. (I.e. the strings desired to be part of the chord pressed fall at points where the dampening padding has been cut away.) Groupings of chords are typically of 12, 15, or 21 with 21 providing the greatest flexibility and the least amount of playing space in the high range for the musician's fingers. Said chord bars are retained on the autoharp most commonly in one of two different ways: set into slots with small springs (see (90) in FIGS. 6,7) at the bottom of the slots (to allow the bars to return up off of the strings after being pressed) and a retaining device (10) to keep them from falling out of the slots if the instrument is turned over; or the chord bars are set over small post assemblies (sometimes called “combs” for their general appearance) with small springs, or bent spring flaps instead of springs, and also incorporating retaining devices. The slots and post assemblies are firmly screwed to the body of the instrument for proper alignment with the last chord bars in the sequence exposed at the ends of the overall grouping. (See FIGS. 1 and 2 for a typical chord bar arrangement for items (10), (14), and (8) attached to the main body of the autoharp.) Advancements have been made to instruments of the prior art to allow their chord bar retainers to be easily and quickly removed to permit, in turn, the musician to remove and replace individual chord bars into the slots or over the posts, with the overall chord bar housing (14) staying firmly affixed to the autoharp. However, the practicality of executing this exchange during say an on-stage performance is too risky, cumbersome, and time-consuming for most performers to undertake. It takes a degree of concentration to keep from mixing up the bars (or dropping them!) and if they are placed in the wrong position, the musician will be unable to effectively play the instrument. The common mode of operation, therefore, is to have multiple instruments on stage to ease the problematic nature of exchanging chord bars between songs and to provide a full range of “color chords” literally at one's fingertips.
Non-professional autoharp musicians tend to play with the most common chord bars required for a reasonable range of tonal keys and tend to forgo trying to accommodate “color chords” (those which add more tonal interest to a given composition). They also will often forego playing in some desired keys to avoid buying and keeping more than one autoharp. Most instruments of the “chromatic” style configuration contain as many chords as possible, along with “lock bars” for diatonic style play, to eliminate the need for having additional instruments to cover extra desired tonal keys. The practical limit for typical autoharps is 21 chord bars, which leaves very little physical space to play the shortest strings on the instrument. Because of this problem professional autoharp players often will carry several autoharps to concerts to allow finger room to play in the different keys required for their repertoire. The more chord bars on the autoharp the less space for the musician's fingers to strum and pluck the stings. Thus, fewer chord bars enhances playing potential.
Some autoharp players prefer the sound of strings that are plucked or strummed closer to the bottom slotted string bridge (42) and therefore make the decision to mount the chord retaining device (14) further away from the bridge to allow finger movement space over the lower portion of the autoharp. This effectively eliminates their ability to play sound selections on the same instrument that would benefit from the softer sounds that result from plucking and strumming strings closer to the center of the strings. In addition, when chord bars are mounted closer to the center of the autoharp the potential for discordant harmonics is greater since many possibilities in this configuration exist for dampening pads to impact strings at their midpoints or third points.
Harmonics Avoidance
The prior art of chorded zithers/autoharps has been significantly encumbered by the problem of discordant harmonic sounds compromising otherwise harmonious-sounding chords. The problem manifests itself when a string dampening chord bar pad (44) of the instrument contacts a string (that is not desired in the particular chord) at a harmonic point (usually at one half or one third its span from bridge-to-bridge) and is unable therefore to fully dampen the sound of said string. The resultant ring-through sound diminishes the quality and clarity of the desired chord. It is very difficult to avoid every harmonic point on a chorded zither/autoharp, especially in chromatically configured instruments with more than 15 chord bars. (If only a few chord bars are provided on the instrument they usually avoid the most problematic harmonic points.) It is also difficult to avoid the harmonic problem points in instruments where the chord bars can be removed individually and replaced with chord bars in different keys, because it is virtually impossible to position all possible chords so that no dampening pads will hit a harmonic point on the strings. When instruments are set up with the chord bars mounted further from the bottom string bridge the problem becomes more acute since the number of potential harmonic points increases.
The prior art attempts to avoid the majority of problems by two general methodologies: 1) Reducing the quantity of chord bars that can be played on a given instrument, thus keeping the number of chord bars that physically begin to overlap the harmonic zones at a minimum, or 2) Positioning as many chord bars as possible just off of the harmonic problem points. Some autoharp instrument builders have tried to revise the design of the dampening pad itself to minimize the problem harmonic but with limited results because the footprint of the dampening pad still falls within the string's harmonic zone.